Cyanobacterial Blooms: Carbon and Nitrogen Limitation Have Opposite Effects on the Buoyancy of Oscillatoria

Abstract

Gas vacuolation in Oscillatoria rubescens decreased with increased nitrogen limitation and increased with transitions from nitrogen to inorganic carbon limitation. Gas vacuoles consist of protein vesicles that can accumulate in carbon- limited but not in unenriched nitrogen-limited cells. Nitrogen limitation is a factor in the formation of deep population maxima; carbon limitation can promote surface blooms.

Cyanobacterial dominance: The role of buoyancy regulation in dynamic lake environments

“…Direct evidence has come from the cyclostat experiments of Klemer et al (1982) who found increased gas vacuolation in Oscillatoria under C limitation. Walsby & Booker (1976) found less surface accumulation of A. flos-aquae in the half of a partitioned laboratory-column treated with carbonate while Paerl & Ustach (1982) found that the buoyancy of Aphanizomenon flos-aquae was highest under CO2-limiting conditions.…”

“…Moreover, if additional supplies of limiting nutrients are made available to stratified populations, Oscillatoria spp. will move up to a new position in the light gradient where a new balance between carbon fixation rates and nutrient availability may be struck (Klemer 1976(Klemer , 1978Klemer et al 1982). Presumably, this upward migration could depend, in part, upon renewed gas-vesicle synthesis.…”

“…isothrix enclosed in in situ columns (Klemer 1973) or bottles (Walsby & Klemer 1974) resulted in increased buoyancy. Booker & Walsby (1981) used an experimental laboratory water column to demonstrate that when grown in "complete" medium, Anabaena flos-aquae became extremely buoyant and aggregated at the surface, whereas under either phosphate or sulphate limitation the organisms stratified at a depth of c. 1 m. Klemer et al (1982) used cyclostats to demonstrate that carbon and nitrogen limitation have opposite effects on the buoyancy of Oscillatoria rubescens, nitrogen limitation resulting in a decreased gas vacuolation while transition to carbon limitation brought about increased vacuolation. These changes in gas vacuolation resulted in the loss or gain of buoyancy.…”

Health hazards for terrestrial vertebrates from toxic cyanobacteria in surface water ecosystems

“…Specific physiologic capabilities of cyanobacteria enable them to compete very efficiently with other photosynthetic microorganisms. Most cyanobacterial species regulate their buoyancy (by means of gas-vacuoles) and this allows them to colonize different depths in the water column depending on the localization of nutrients and the availability of light [63,122]. Possession of accessory pigments, such as phycoerythrin, allows several species to carry out photosynthesis at depths that receive only green light and where, in addition, nutrients are more abundant than on the surface (surface waters are rapidly depleted following spring algal proliferations).…”

The role of macronutrients (C, N, P) in controlling cyanobacterial dominance in temperate lakes

“…The average C : N : P ratio by weight of the seston in these lakes was 130 : 13 : 1 while ratios of unfertilised lakes were slightly less (118: 11 : 1, Schindler 1971). Carbon may nevertheless influence the relative proportion of cyanobacteria (Shapiro 1973), scum formation (Paerl & Ustach 1982), and migration behaviour (Klemer et al 1982) -particularly in low-alkalinity waters. In a series of enclosure experiments in Lake Emily, Minnesota, Shapiro (1973) found that the addition of CO 2 and nutrients N and P at a supply ratio of 7 shifted the community dominance to chlorophytes.…”